Nubira II engine upgrade - similarities to Opel C20XE

[nickRP]

Hello guys!

I am not really into Daewoo/GM tuning, so I need your help. A friend of mine has 2003 Nubira Station Vagon. The engine is 2.0 16v, rated at 133bhp.

My first question is how similar is this engine to Opel C20XE? Apparently there is a lot of things in common - but I am interested whether cams and/or complete valve head can be swapped? Is the bolt pattern for manifolds the same? According to the Mahle catalogue, the pistons are the same, so I will use high compression (10.5:1) Opel items.

As far as engine management is concerned, Opel was using Bosch, so that's another story. But where can I find some data on Delco system used in Nubira? Where the ECU is located? What ECU version should the mentioned Nubira have? Can it be programmed via diagnostic link?

Cheers,
Nick
p.s. My latest Fiat project can be found at: http://turbotipo.hollosite.com/

[GsiTurbo]

Welcome to the board!

The engine is basically the X20XEV found in the 2.0 Vectra G (??) and Astra G. Comparison-wise, its the C20XE bottom end, but with press-type pistons pins, as opposed to floating found in C20XE (or is it the other way around?)

Cams cannot be swapped due to fact the Nubi engine uses DIS, while C20XE is driven off the distributor cap. I believe the exhaust manifold bolt pattern is the same, but the head itself is slightly different (like smaller valves and both the intake and exhaust runners).

The C20XE head can be swapped, but together with the timing belt drive system, which is slightly different.

The ignition system should be identical as one used in the X20XEV, with different programme to meet the north american emmision regulations, which are different from euro-4. The Nubira's ECU can be flashed with a different program via the diagnostic link, as it was done on Erfinder's Lacetti due to recall.

Hope this helps.

[nickRP]

Thank you very much for the reply.

Yes, you were right, C20XE has floating pin, while X20XEV has fixed pin. In the Mahle catalogue, I found that X20XEV has CR of 10.8:1. That is different from Nubira engine, so Nubi obviously have different pistons. Options would be to use X20XEV pistons for increased CR, or use C20XE pistons and rods, gaining the slight advantage of using floating pins along with increased CR.

There is a distributorless C20XE, employing Bosch Motronic 2.8. Maybe cams from this variant would be a straight fit. On other hand, changing complete head would yeild much more power potential, so this would be my preferred way (together with intake manifold and exhaust header). Do you know intake/exhaust valve diameters on Nubi? Can you please tell me in more details what has been changed in timing belt drive system, which components I would have to source if I decide to change the head?

Is there any known comercial or DIY package for communicating to Nubira ECU (diagnostic codes, parameters, flashing)?

My goal would be in 170bhp range, without hurting low end performance (as much as it is possible).

Regards,
Nick

[Carr]

Sorry to bring up a very old thread, but it is pretty much exactly what I am looking at.

I was looking to get my head reconditioned but it was going to cost me something like $1400 so I was looking at other options. I think I have come across a cheap C20XE (hopefully it isn't the C20NE), about $150 with box and computer. If I were to get this engine, what would be my best option.

1. Change complete engine
2. Change the head, intake, exhaust and other required parts

From what I have read if I went with option 1, I think I would need to rewire the car to suit the Bosch computer which is a bit of a pain but could be done. Does anyone know if the engine mounts would be the same?

I read somewhere with option 2, there are differences with the timing belt. Anyone have any more info on this?

I haven't done anything like this before but don't think I would have too many problems doing it if I had the service manuals for both engines/vehicles.

Please feel free to point out anything that I have overlooked or add any advice. Any and all input is welcome.

Cheers
Chris